This Reische 170° thermostat is custom made with the same size diaphragm and bypass control as the OEM units. This provides proper bypass control, which means maximum efficiency from your Mustang or F150s cooling system. Each of these thermostats is carefully modified by hand, using only U.S. made parts and then quality inspected to ensure reliable and consistent opening temperatures. This Reische Performance 170 Degree Thermostat for all 2011, 2012, 2013, 2014 and 2015 V6 and GT Mustangs, all 2012-2013 Boss 302 Mustangs and all F150s with a 3.5L EcoBoost Engine, is a direct replacement for the old, standard issue thermostats.

This Reische Performance Thermostat is intended to be used in vehicles that are running a custom tune. It is important that the fan settings in your tune are set up properly if you want to see the best possible heat dissipation from your cooling system. Otherwise, a low temperature thermostat will only be effective when the vehicle is moving because heat cannot be removed unless there is air passing through the radiator. Whether you are using an aftermarket radiator or not, this thermostat will provide the best possible heat dissipation from your setup, along with a faster warm up time and better cold weather performance than a 160° unit or a thermostat that merely had holes drilled in the diaphragm.

Beware of aftermarket companies who sell a general thermostat for all Ford modular engines. Reische Performance thermostats are the only ones designed precisely for a proper fit on each particular application, making them the best performing low temp units on the market! Typically with Reische’s 170° Performance Thermostat installed, your cooling fans should be set to turn on between 184-190° and shut off between 176-182° for optimal results, if not then re-flash your tune with the appropriate settings.

Will I benefit from a low temperature thermostat?

A lot of people ask this question and the short answer is-probably. But typically it isn’t recommended if your engine is still running on a stock tuning. Simply because an engine is cooler does not necessarily mean it will make much more horsepower. You may lose a few degrees of incoming air temperature and see some small gains but primarily, you can think of lower coolant temperatures as protection against engine-damaging detonation. When trying to accelerate an overheating vehicle, detonations can quickly destroy a high horsepower engine that is being pushed to maximum levels of performance. But aside from saving your engine there are a couple ways that a low temperature thermostat will actually help increase the power in your 2011, 2012, 2013, 2014 or 2015 V6 or GT Mustang, or any 2012-2013 Boss 302 Mustang or in any F150 with a 3.5L EcoBoost Engine.

An engine at 185° can run more timing advance safely than one running at 205° so tuning, along with a low temperature thermostat, can make some significant gains. So if you're using a handheld programmer, chip or custom tune then yes, a 170° thermostat is definitely recommend. Running an engine cooler has been an A-B-C of high performance since the early days of hot rodding, just ask your dad or grandfather. Those guys were pulling out their thermostats or drilling holes in them because they knew they could run more timing by doing so.

What are the possible negative effects of a low temperature thermostat?

If the engine does not reach a high enough temperature for the computer to leave warm-up mode then fuel economy will drop drastically. However in all the time this 170° Performance Thermostat has been produced there has not been one complaint of anyone losing fuel economy. Reische believes that 170° provides the best balance overall for your engine.

Another concern is oil temperature and viscosity. If the engine oil does not get hot enough to burn off certain contaminants then the oil's effective life will be reduced. Lab testing has not shown any significant contaminant increases using our 170° thermostats in cold weather, but to be safe, it is recommended to change your oil more frequently if you plan to operate your vehicle regularly in cold climates. Also, effective oil viscosity is increased with lower temperatures so using a quality 0W-30 (or 5W-30) synthetic oil for most late model applications is ideal.

In extreme cold environments it may be best to run an OEM temperature thermostat but above all, monitor your coolant temperature carefully whenever you do have concerns. If you observe sustained engine coolant temperatures below 165°, then it is recommended to swap in the OEM thermostat for use during the colder months.

The specialists at Reische believe that a 170° opening temperature provides the ideal balance for high performance engines, supplying high flow to your radiator by mid-180 temperatures while still providing good all season performance. With proper fan settings your coolant temperatures in cool weather should be in the 170s and in hot weather the 180s, giving those running high levels of timing and/or boost added protection against engine-damaging detonation as well as maximum power output.

*All Reische Performance thermostats ship with a new gasket and coolant ratio/additive recommendations.